Terms and Abbreviations

Help Contents
Abstract Syntax Notation One (ASN1)
A standard and notation describing how data is encoded, transmitted and decoded.
Analog to Digital Converter (ADC)
A device for converting a continuous measurement, for example voltage, to a digital number to represent the measurement.
An abnormal condition usually requiring manual intervention to resolve.
Alarm List
A list of Alarms showing a summary of the abnormal conditions in plant and equipment.
American National Standards Institute (ANSI)
A non-profit organization that oversees the development of standards for products, systems and personnel in the United States.
Information represented by a continuously variable physical quantity. For example voltage, current, temperature, pressure.
Application Programming Interface (API)
A set of functions and tools for building software applications.
American Standard Code for Information Interchange (ASCII)
A Character Encoding standard, published by the American National Standards Institute (ANSI) to represent text in computers. ASCII is a 7 bit code defining a total of 128 characters.
A measurement of communication data rate named after Émile Baudot. The Baud Rate is the number of information symbols transmitted per second.
Character Encoding
A method of representing a set of characters by an encoding. Examples of character encoding include:
Client Server Protocol Version 4 (CSPv4)
A proprietary Ethernet based communication protocol used by Allen Bradley PLC5, MicroLogix and SLC PLCs.
Common Intermediate Language (CIL)
A low level programming language that is independent of the hardware platform it is run on. See also Microsoft Intermediate Language (MSIL).
Common Language Runtime (CLR)
Part of .NET platform by Microsoft. An environment which runs Common Intermediate Language (CIL).
Communication Channel
A pathway for sending and receiving data to a remote device. The pathway can be physical (using wires or fiber-optic cables) or broadcast (radio signal).
Communication Protocol
A set of rules for exchanging data between two devices. Examples of communication protocol include Modbus, Factory Intelligent Network Service (FINS), Simple Network Management Protocol (SNMP).
Comma Separated Values (CSV)
A text file format where values are separated by the comma (,) character and records are separated new lines. CSV is not a formal standard. The Internet Engineering Task Force (IETF) has published memo RFC 4180, which describes the format and layout of CSV files.
Computer Aided Design (CAD)
The use of computer systems to aid the creation and modification of a design.
Common Industrial Protocol (CIP)
An open standard protocol that defines a set of common messages and services for control and automation applications.
Condition Event
A type of Event that records the change in state of an Alarm in the Event Log.
Configuration Tool
A software program to configure Fernhill SCADA.
Coordinated Universal Time (UTC)
The primary time standard by which the world regulates clocks and time.
Data Acquisition (DAQ)
A way of sampling real world signals and converting these signals to a digital form that can be stored and processed by a computer.
Data Driver
A type of Driver that reads data from a Programmable Logic Controller (PLC) or other type of data source.
A serial communication protocol for Allen Bradley PLCs.
A measurement expressed in terms of discrete steps.
Distributed Network Protocol 3 (DNP3)
A communication protocol for transferring data from an Outstation to a SCADA System. The DNP3 specification defines both static data (data without timestamps) and event data (data with timestamps). The use of event data (data with timestamps) offers these advantages over PLC communication protocols:
Domain Name System (DNS)
An internet service that translates a domain name to an IP Address.
Data Source Name (DSN)
The name associated with an Open Database Connectivity ODBC data source.
Drawing Interchange Format (DXF)
a Computer Aided Design (CAD) data file format developed by Autodesk for exchanging drawing files between applications.
A software component to interface to another software program or hardware device.
Electronic Mail (email)
A method of exchanging messages between people using electronic devices.
A family of computer networking technologies defined by the IEEE 802 standards.
An industrial network protocol that defines how Common Industrial Protocol (CIP) messages and services are transported over an Ethernet network.
A record of an incident or change that is important and recorded in the Event Log. There are three types of event: Simple Events, Tracking Events, and Condition Events.
Event Log
A collection of Events timestamped and stored historically.
Factory Intelligent Network Service (FINS)
A communication protocol developed by Omron. Intended to be used between Programmable Logic Controllers (PLC) and other devices.
Graphical Device Interface (GDI)
A part of the Microsoft Windows operating system that draws lines, shapes and text on a display device.
Graphics Interchange Format (GIF)
A raster graphics file format that uses lossless data compression. The file format uses the Lempel–Ziv–Welch (LZW) compression algorithm.
Graphic Page
A page that shows the state of plant and equipment using graphics and text.
Graphical User Interface (GUI)
A way of interacting with computer devices using graphics and text.
IEC 61131-3 Standard
A standard defining five programming languages for Programmable Logic Controllers (PLC).
Internet Engineering Task Force (IETF)
The standards body, whose mission is to produce high quality technical documents that influence how people design, manage and use the Internet.
Internet of Things (IoT)
A network of physical devices that connect and exchange data.
Internet Protocol (IP)
A set of Communication Protocols used on the Internet and similar networks.
Internet Protocol Address (IP Address)
A numeric label assigned to each device on a network that uses the Internet Protocol (IP).
Internet Standard
An Internet Standard is a specification applicable to the Internet. Internet Standards are published and maintained by the Internet Engineering Task Force (IETF).
Java is a general-purpose computer programming language that is designed to run on different platforms without the need for recompilation.
A raster image file format that uses lossy compression.
JavaScript Object Notation (JSON)
A lightweight data interchange format based on a subset of the JavaScript Programming Language. JSON is defined by the following standards: ECMA-404 and RFC 8259.
JSONata is a lightweight query and transformation language for JSON data.
Lempel–Ziv–Welch (LZW)
A lossless data compression algorithm.
Melsec Communication (MC)
A communication protocol for communicating with Mitsubishi Programmable Logic Controllers (PLC).
Microsoft Intermediate Language (MSIL)
A low level programming language that is independent of the hardware platform it is run on. The term MSIL has been superceded by Common Intermediate Language (CIL).
A communication protocol published by Modicon (now part of Schneider Electric). Intended to be used between Programmable Logic Controllers (PLC) and other devices. The original standard defined two variants: Modbus ASCII - a protocol that uses only ASCII characters, and Modbus RTU - an 8-bit binary protocol. A later addition to the standard defined Modbus TCP - a way of sending modbus messages over a TCP/IP Network.
Modbus ASCII
An encoding of the Modbus protocol that uses a subset of the ASCII character set.
Modbus RTU
An encoding of the Modbus protocol that uses 8-bit binary characters.
Modbus TCP
An encoding of the Modbus protocol for transmission over a TCP/IP Network.
Message Queuing Telemetry Transport (MQTT)
Message Queuing Telemetry Transport (MQTT) is publish-subscribe messaging protocol built on top of TCP/IP. The MQTT protocol is defined in standard ISO/IEC 20922.
Notification Area
Part of the Windows Taskbar that provides temporary status notifications. It is used to display icons for system and program features that run in the background. The Notification Area has historically been known as the System Tray.
Open Database Connectivity (ODBC)
A standard interface to access databases using SQL queries.
A command line tool for registering ODBC drivers and Data Source Names (DSN).
Object Identifier (OID)
A sequence of numbers used to provide a name for an object.
OLE For Process Control
An obsolete term for OPC.
A set of standards, published by the OPC Foundation, for data exchange between data monitoring and process control applications.
Open Graphics Library (OpenGL)
A platform and language independent Application Programming Interface (API) for drawing 2D and 3D Vector Graphics.
Open Systems Interconnection (OSI)
A standard defining how messages should be transmitted on a network.
Operator Interface
A type of Graphical User Interface that presents plant and equipment data to a user. Information is presented using Graphic Pages, Trends and Data Lists. Using an operator interface, a user can monitor and interact with plant and equipment.
A device located at a remote location used to record data.
Personal Computer (PC)
A compact computer designed for personal use.
Portable Network Graphics (PNG)
A raster graphics file format that uses lossless data compression. Originally created as a replacement for Graphics Interchange Format (GIF)
Programmable Controller Communication Commands (PCCC)
A set of commands for communicating with Allen Bradley PLCs. PCCC commands can be transported over DF1 or Ethernet/IP.
Programmable Logic Controller (PLC)
A digital computer used for automation of a process.
A set of rules defining how two or more devices communicate.
An abbreviation for Red, Green and Blue.
A public key cryptosystem invented by Rivest, Shamir and Adleman. To use the RSA cryptosystem four steps are required: 1) The recipient creates a public and a private key pair. 2) The recipient publishes the public key and keeps the private key secret. 3) The sender encrypts a message using the public key and sends the encrypted version to the recipient. 4) The recipient decrypts the message using the private key.
An electrical specification for Serial Communication (sending data 1 bit at a time). The RS-232 standard defines: RS-232 is suitable for transmitting data over short distances of up to 5 metres.
An electrical specification for Serial Communication (sending data 1 bit at a time). The RS-422 standard uses differential signalling using a two conductors: RS-422 is suitable for transmitting data at up to 10 Mbps (megabits per second), or distances of up to 1500 metres.
Secure Sockets Layer (SSL)
A cryptographic protocol, originally designed by Netscape, to provide secure communications between two end points. Secure Sockets Layer (SSL) has been superceded by Transport Layer Security (TLS).
Serial Communication
A method of sending data 1 bit at a time over a Communication Channel.
Simple Event
A type of Event that records an important incident or change in Fernhill SCADA in the Event Log. Simple events do not have any user association.
Simple Network Management Protocol (SNMP)
An Internet Standard Protocol for managing devices on an IP Network. Devices that support SNMP include routers, switches, servers, workstations, printers and so on. SNMP is widely used in network management systems to monitor devices for abnormal conditions that require intervention.
Simple Mail Transfer Protocol (SMTP)
The Simple Mail Transfer Protocol (SMTP) is an Internet Standard Protocol for sending electronic mail (email). The SMTP protocol is described in RFC 5321. The format of messages sent using SMTP is described in RFC 5322.
Structured Query Language (SQL)
A programming language used for database management.
Structured Text (ST)
A block structured programming language defined in the IEC 61131-3 standard.
Supervisory Control and Data Acquisition (SCADA)
An industrial computer system that monitors and controls a process. A SCADA System typically consists of:
System Tray
An obsolete term for the Notification Area.
An entry in the tag database that represents a single measured value, device or communication channel.
A date and time value identifying the precise moment in time of an event.
Transport Layer Security (TLS)
A cryptographic protocol to provide secure communications between two end points. Transport Layer Security (TLS) builds on Secure Sockets Layer (SSL).
Tracking Event
A type of Event that records an action by a user in the Event Log.
Transmission Control Protocol (TCP)
A set of rules for ensuring data sent on a network is delivered in the same order it was sent without loss or duplication. TCP is one of the core protocols in the Internet Protocol (IP) suite. The Internet Engineering Task Force (IETF) is the body responsible for maintaining and developing the TCP specification. The first specification RFC 675 was published in 1974, and later updated to the Version 4 specification RFC 793 in 1981.
Transport Service Access Point (TSAP)
An end point for communication when using the Open Systems Interconnect (OSI) reference model.
A graph that shows how process variables vary over time.
Trivial File Transfer Protocol (TFTP)
A simple protocol for transferring files, where user authentication is not required.
User Account Control (UAC)
A security mechanism in Microsoft Windows that limits applications to standard privileges until approved by an administrator.
A standard for consistent handling and encoding of text used by most of the writing systems in the world. Unicode defines code points for writing scripts in current use, obsolete writing scripts and symbols.
Unicode Consortium
A non-profit organization responsible for the development of the Unicode standard.
Uniform Naming Convention (UNC)
A syntax used on Microsoft Windows to describe the location of a network resource.
UNIX is a multi-user and multi-tasking operating system originally developed at Bell Labs in the 1970s. Since its original development, there have been many different variants of Unix like operating systems developed including Linux.
An ODBC Driver Manager for UNIX operating systems.
User Datagram Protocol (UDP)
A set of rules for sending messages on a network. UDP is one of the core protocols in the Internet Protocol (IP) suite.
See Coordinated Universal Time (UTC).
Unicode Transformation Format – 8-bit (UTF-8)
A Character Encoding standard, defined by the Unicode Consortium. UTF-8 uses between 1 and 4 bytes to represent the 1,112,064 valid code points in Unicode.
Unicode Transformation Format – 16-bit (UTF-16)
A Character Encoding standard, defined by the Unicode Consortium. UTF-16 uses 1 or 2 16-bit words to represent the 1,112,064 valid code points in Unicode.
Unicode Transformation Format – 32-bit (UTF-32)
A Character Encoding standard, defined by the Unicode Consortium. UTF-32 uses 32-bit words to represent the 1,112,064 valid code points in Unicode.
Vector Graphics
The use of polygons and lines to represent images in computer graphics.
A character, or series of characters, that represents horizontal or vertical space.
Windows Service
A computer program that runs in the background on Microsoft Windows NT Operating Systems.